Automotive Walnut Blaster - Engine Carbon Cleaner 

Carbon deposits in engines are a big problem and the issue seems to be getting worse.
For those that have not heard of walnut blasting, this is how a walnut blaster works…
You must remove the intake manifold off the vehicle. Once clear access has been gained, fill the unit with walnut shells (around 2 - 3 kgs)
Gathering both the high pressure gun and the vacuum hose, stick the high pressure gun shaft through the small side opening on the flexible rubber vacuum hose and position the vacuum hose over the inlet port you want to clean.
This allows you to not only blast the walnut shells into the intake ports and over the valves but at the same time vacuum up the excess shells and carbon deposits while making minimal mess.
The time it takes for the clean will vary from vehicle to vehicle naturally, but once the inlet manifold is off it does not take long to complete the clean.

Many manufacturers list walnut blasting as the "official way" to clean a carbon affected vehicle and the results speak for themselves.
These units are great priced tools for workshops dealing with carbon affected vehicles!

What is carbon deposition?

There are hydrocarbon olefin residues that attach on the engine intake / valves & cylinder pistons when the fuel burn in the engine is not complete. 
These residues change into hard black shells in high temperature conditions, that is what is called carbon deposition.

Why the need for cleaning carbon deposition?

Carbon deposition will decrease air-fuel ratio, cut down engine output power, increase fuel consumption, and in bad cases gather around the valves causing the valves not to seat properly causing engine misfiring or intermittent shake on idle.

All these things if left unattended will hurt and engine.

Ideally this should become a regular scheduled maintenance event after every 40,000 - 50,000 kilometers.

What is walnut powder / sand / shells

Walnut sand or shells is a pure natural material.
Its hardness rating is lower than metal but higher than carbon deposits making it ideal to clean the intake pipe and back side of intake valves thoroughly with no damage to engine metal parts.
Walnut shells can also be purchased from Ozwide Tools in convenient 1kg packs.